Plastic filter tube for lining e.g. drainage bore hole - has internal axial reinforcing ribs and saw cut slots in tube wall

摘要

Filter tube is for placing a bore hole e.g. for land drainage by pumping-out water or for obtaining potable water. It pref. consists of plastics and is provided with reinforcing ribs extending axially along its inner wall whilst slots are cut through the wall only, by sawing. The ribs may contain embedded cables or fibre strands to confer increased tensile or bending strength. The cuts are pref. helical but may be circular. The ribs may be formed by longitudinally extending depressions in the tube wall.